I know they say never say never in WWE, but Cena holding the NXT title is probably a safe bet in the never category.
What's the upside to a Cena reign? What does it really accomplish? The NXT brand is already hot as hell, and John Cena is essentially feuding with it in a lot of ways. That in of itself is far more elevating than a title reign.
Cena would have to drop that title. That would lower the significance of Kevin Owens' victory. Even if shenanigans were involved, Cena would want kayfabe revenge, so how long would his NXT reign last for?
Cena will not appear on NXT programming. It's not his character to run in and cost someone their title, it would be in his character to even the odds if Owens were cheating. NXT doesn't need Cena, and the NXT fans would boo Cena out of the building.
Cena holding the NXT title, a developmental title, only damages Cena and pisses off the NXT fans. If anyone from the main roster were to hold it, it would be someone at the end of their career like a Mark Henry or a Christian.
I don't see Owens dropping his title, unless he cheats and a babyface evens the odds. He could lose it in a multi-man type match, where he's distracted, but even that doesn't feel right.
My prediction is Owens vacates the title when the decision is made to move him to the main roster full time. Sami Zayn should beat Owens, but I doubt they go their even with an unclean finish. If anyone wins clean, it's Samoa Joe without a doubt.
WWE belives in Balor and he will hold the WWE world title some day, but I don't see them putting him over Owens clean. Owens is being built into the next monster heel. He'll be the first truly Triple H guy to hold the WWE title. The Japan live event is two weeks before Battleground, I doubt Owens drops the NXT title so close to what will likely host his third meeting with Cena.
Interesting though, a title vs title match is certainly under consideration, but John Cena will never hold the NXT title.